The national seismic hazard maps do not show the effects of local geology. Regional and urban seismic hazard maps include the effects of local geology and soil response in their estimates of ground shaking. On the embayment regional seismic hazard map, the local geology "deforms" the simple racetrack looking hazard contours you see in the national seismic hazard map. Sometimes the effect of local geology is to smooth out the seismic hazard over a large area as seen in the Memphis urban hazard map.